cosmic dust

(dust)

(cosmic dust is dust in space such as interstellar dust)

Cosmic dust is a general term for dust in space,
which includes intergalactic dust, interstellar dust,
and interplanetary dust.
Dust leads to extinction, making observation of
stars and other astronomical bodies more difficult,
but is also observed both for itself and for the
conclusions that can be drawn from reradiation
and scattering.

Though termed "dust", it can be orders-of-magnitude smaller than
everyday dust: in the interstellar medium, what are termed dust particles
(or referred to as particles)
are a few molecules, though in the interplanetary medium,
presumably all sizes particles exist, from micrometeoroids down.

Much dust is thought to be formed by stars toward
the end of their main sequence, such as red giants.
It is also formed or scattered by novae
and supernovae. The term nebula has come to be
most commonly used for clouds that include
sufficient interstellar dust to be opaque
to visible light.